Device for providing controlled movement

ABSTRACT

A device for moving a member by a controlled amount or to a controlled position. An element undergoing a rotary vibrational movement is coupled to rotate a rotatable member when the element vibrates in one direction but not when the element vibrates in the opposite direction, causing a slight incremental advance of the rotatable member in the one direction for each cycle of the vibrating element.

United States Patent Bush June 6, 1972 [54] DEVICE FOR PROVIDINGCONTROLLED MOVEMENT ['72] Inventor: George L. Bush, Stamford, Conn.

[73] Assignee: The Bunker-Ramo Corporation, Oak

Brook, [IL

[22] Filed: Feb. 16, 1970 21 App]. No.: 11,746

52 us. c1 ..74 12s.s,31o/21 51 ..F16d27/l0 58 Field of Search ..192 45,44; 74/573, 574, 125.5;

[56] References Cited I UNITED STATES PATENTS 1,322,659 11 1919 Volkers..31o 21 2,954,491 9/ l 960 Digirolamo ..3 1 0/21 2,286,419 (SH 942Krenzke 1,838,389 l2/l93l Goldberg 2,829,526 4/1958 Riordan et al...74/29 Primary Examiner-William F. ODea Assistant Examiner-Wesley S.Ratliff, Jr. Attorney-Frederick M. Arbuckle 57] ABSTRACT A device formoving a member by a controlled amount or to a controlled position. Anelement undergoing a rotary 'vibrational movement is coupled to rotate arotatable member when the element vibrates in one direction but not whenthe element vibrates in the opposite direction, causing a slightincremental advance of the rotatable member in the one direction foreach cycle of the vibrating element.

4 Claims, 4 Drawing Figures CONT'ROL fill/D DEVICE FOR PROVIDINGCONTROLLED MOVEMEN'I This invention relates to a device for moving amember by a controlled amount, or to a controlled position, and moreparticularly, to a device for converting a vibrational movement into acontrolled movement in a desired direction.

There are numerous applications where it is required to either moveamember to a selected physical position, or to impart a predeterminedincrement of movement to a member. In one such application, a drumcontaining numerical indicia is mounted on a shaft and, in response to apredetermined input, the shaft is rotated until a selected numeral onthe drum is in a display position. In existing devices for performingthis function, a train of pulses is utilized to step the drum from oneindicia position to the next until either an indication is received thatthe desired numeral is in a display position, or until the requirednumber of pulses to step the drum to the desired position have beenreceived. With such a drive mechanism, the steps are relatively large.Significant energy is therefore required to overcome the inertia of thedrum for each step and significant energy is required to stop the drumafter each step. The repeated shocks resulting from starting andstopping the drum cause strain and wear on the components utilized,limiting the useful life of the device and increasing the requiredmaintenance. In this application, a device which would significantlylower, start and stop inertias would therefore permit the use of asmaller, less expensive, drive element, would reduce the power drain ofthe device, would reduce the size and weight of components in the devicebecause of the lower stresses which it would be called upon towithstand, would increase the useful life of the components, and wouldreduce maintenance costs.

' In other applications it is desired to move a member, eitherrotationally or linearly, by a very small amount, to a very closelydefined position. I-Ieretofore, complicated gear trains and like deviceshave been utilizedin order to obtain such positional control. A needtherefore exists for a small, simple, inexpensive device for providingmovement in small increments to a finely controlled position.

It is therefore a primary object of this invention to provide animproved movement control mechanism.

A more specific object of this invention is to provide a rotary movementcontrol mechanism which permits relatively large movements to acontrolled position with minimum start and stop inertia.

Another object of this invention is to provide a device for moving amember in very small increments to a finely controlled position.

Still another object of this invention is to provide a movement controldevice of the type indicated which is relatively small, simple, andinexpensive- In accordance with these objects, this invention provides adevice for providing a controlled movement, and, more particularly, acontrolled rotary movement, which includes a means for providing arotary vibrational movement and a means for joining the memberundergoing said rotary vibrational movement to a rotatable member in amanner such that the members are free to rotate relative to each otherin only one direction. Thus, for each cycle of vibration of the rotaryvibrational movement, the rotatable member is incrementally rotated in aselected direction. This incremental rotary motion may be converted intoa linear motion through, for example, a rack and pinion mechanism.

In a preferred embodiment of the invention, the rotary vibrationalmovement is obtained from a means for generating a vibrationalmechanical movement which is coupled to a rotatable member by a bandsecured at one end to the vibrational movement means, and is mounted onthe rotatable member in a manner to impart a rotary vibrational movementthereto.

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of preferred embodiments of the invention, as illustrated inthe accompanying drawings.

In the drawings:

FIG. 1 is a side view of an illustrative embodiment of the invention.

FIG. 2 is a top view taken along the line 2-2 of FIG. 1.

FIG. 3 is a side view of an alternative embodiment of the invention.

FIG. 4 is a bottom view of a shown in FIG. 3.

Referring now to FIG. 1, it is seen that for an illustrative embodimentof the invention, a vibrating relay 10 is secured to a C-shaped housing14 by a screw 16 or other suitable means. AC excitation from a source 20is applied to relay 10 through a switch 22. Switch 22 may beany'standard electronic or electromechanical device adapted to performthe required function. For simplicity of illustration, switch 22 hasmerely been shown as a can mounted on a similar can containing a controlcircuit 24 the function of which will be described later. The cancontaining circuit 24 is secured to housing 14 by screws 26 or othersuitable means.

As relay 10 is energized, relay armature 28 is vibrated in thedirections indicated by line 29 (FIG. 2). A band 30 of a flexible, butnonextendable, material is secured at one end to armature 28 and passedaround a wheel 32 in a counterclockwise direction as viewed in FIG. 2.Band 30 terminates in a connection to one end of a tension spring 36.The other end of spring 36 is secured to a post 38 mounted on housing14. Band 30 is secured to wheel 32 by clamp 40.

Wheel 32 is secured to the outer shell of an overrunning clutch 42.Clutch 42 and a second overrunning clutch 46 are mounted on a shaft 44.Rotation of the outer shell of clutch 46 is prevented by securing it toa gimble 48 which is mounted on housing 14. Clutches 42 and 46 may beany of a variety of standard overrunning clutches which are adapted topermit a shaft passing through the clutch to rotate relative to theclutch in one direction but not to rotate relative to the clutch in theother direction. A clutch suitable for use in this invention is shown inUS. Pat. No. 3,184,020 entitled Overrunning Clutch and Cage Thereforeissued to Carl F. Benson et al. on May 18, 1965 and assigned to theTorrington Company. For purposes of illustration, it will be assumedthat clutch 42 does not permit relative movement between wheel 32 andshaft 44 when wheel 32 is rotated in the counterclockwise direction, asviewed in FIG. 2, but does pennit relative movement between theseelements when the wheel is rotated in the clockwise direction. Clutch 46permits shaft 44 to rotate relative to housing 14 in thecounterclockwise direction but locks the shaft against rotation in theclockwise direction.

Shaft 44 is mounted for rotation in housing 14 on gimbles 48 and 50 andalso has mounted thereon an indicator drum 52 and a code disk 54. Drum52 may, for example, have a plurality of numerals imprinted on itsperiphery and may be utilized as an indicator element of a displaydevice. Code disk 54 may be any one of a variety of devices having, forexample, concentric rings with selectively conductive areas, magneticareas, or optically clear and opaque areas. A suitable transducer 56 isprovided to read the coding on disk 52 and to provide on lines 58 acoded electrical indication of the present rotational position of shaft44 (and thus also of drum 52). The position indicated on lines 58 iscompared in control circuit 26 with an indication of the desiredrotational position of shaft 44 applied to the control circuit throughlines 60. The circuit 24 controls switch 22 through signals on line 62.

In operation, signals are initially applied through lines 60 to controlcircuit 24 indicating a desired character which is to be displayed ondrum 52, and thus a desired rotational position of shaft 44. If thisposition is different from the present position of the shaft, thesignals appearing on lines 58 and 60 are different. Control circuit 24detects this mismatch and generates an output on line 62 which closesswitch 22 permitting an AC signal from source 20 to be applied toenergize vibrating relay 10. For each cycle of the AC source, band 30 ispulled in a clockwise direction, as seen in FIG. 2, by the action of therelay on armature 28. The band is then pulled counterclockwise back toits original position by the return force of spring 36. During theinitial clockwise movement of wheel 32,

portion of the embodiment the wheel and shaft 44 are decoupled by clutch42. Shaft 44 is locked against movement in this direction by clutch 46.However, since clutch 42 locks wheel 32 to shaft 44 when wheel 32 isrotated in the counterclockwise direction, the counterclockwise returnmovement of wheel 32 results in a corresponding movement of shaft 44 inthe counterclockwise direction. It should be emphasized that bycontrolling the extent of movement of armature 28 and the radius ofwheel 42 the rotational movement of shaft 44 for each cycle of the relaymay be controlled to a very small amount. Since drum 52 and indicatordisk 54 are secured to shaft 44, their rotational position is alsoadvanced. Thus, for each cycle of vibration of relay l0, shaft 44 isadvanced in the counterclockwise direction by a predetermined smallincrement. Since these increments are very small, and occur at arelatively high rate of speed, for example 120 cycles per second, thestart and stop inertia for each increment is virtually nil. Thus, almostall of the power applied to the device is converted into motion.

While the advancing of shaft 44 could occur on either the energizing ofthe relay or on the return as shown, it has been found that the energyin the drive is used more efficiently when advancing the shaft on thereturn. The reason for this is that the energy in the relay is notutilized to overcome the inertia of the driven members but used solelyto stretch the spring. The force required to stretch the spring is leastwhen the armature is furthest from the core and the pull of the core isweakest, and increases as the pull of the core increases. Similarly, themaximum force required to move the shaft and drum is on start-up whenthe force of the spring is greatest. If the relay were also required tosupply the start-up force for the shaft and drum when its pull isweakest, a more powerful relay could be required.

Shaft 44 continues to increment until code wheel 52 is advanced to aposition where the character or position detected by transducer 56 isthe same as that appearing on line 60. At this time, a signal appears online 62 opening switch 22 to terminate the vibration of relay 10. Thiseffectively terminates the incrementing of shaft 44. It is thus apparentthat a device has been provided which can move a member to a preciserotational position in small incremental steps. While, for the displayapplication indicated above, a high degree of precision is not required,in other applications positioning to within a small fraction of a degreemay be provided. The precision of the positioning is to some extentlimited by the smallest unit of measure which can be provided on codingdisk 54.

While the embodiment of the invention shown in FIGS. 1 and 2 is usefulfor many applications, it is limited in that it provides rotation inonly a single direction and that in it provides for only rotarymovement. FIG. 3 shows an embodiment of the invention which is capableof moving a linear member 70 in either direction. Common elements inFIGS. 1 and 3 are similarly numbered.

Referring to FIG. 3, it is seen that the output from AC signal source 20is applied to a control and switching circuit 72. When it is desired tomove rack 70 downward, as viewed in FIG. 4, a switch in circuit 72 isclosed to apply the AC signal from source 20 to a vibrating relay Awhich is the same as the relay 10 of FIG. 1. When it is desired to moverack 70 in the opposite direction (i.e., upward as viewed in FIG. 4) adifferent switch in circuit 72 is closed permitting the AC signal fromsource to be applied to a vibrating relay 108 which again is of the typeshown in FIG. 1.

A band 30A fixed at one end to relay 10A is passed around a wheel 32A inthe same direction as shown in FIG. 2 and terminated in an attachment toone end of a spring 36A. The spring 36A is secured at its other end to apost 38A mounted on housing 14. Wheel 32A is secured to the outer casingof an overrunning clutch 42A having a shaft 74 passing through it. Shaft74 also passes through a second overrunning clutch 46A and terminates ina gimble 48A mounted on housing 14. Clutch 46A is secured to gimble 48Aand functions in the same manner as clutch 48 to permit rotation ofshaft 74 only in the counterclockwise direction. Clutch 42A causes shaft72 to rotate with wheel 32A only when wheel 32A is rotating in thecounterclockwise direction.

Shaft 74 terminates at its other end in differential gear box 76. Gearbox 76 is effective to cause gear 78 to rotate in a counterclockwisedirection when shaft 74 rotates in a counterclockwise direction. Box 76,however, permits slippage between gear 78 and shaft at this time, shaft80 being held against rotation by the action of clutch 468. As will beseen shortly, box 76 also permits slippage between gear 78 and shaft 74when shaft 80 is being utilized to drive gear 78 in the clockwisedirection. As may be best seen in FIG. 4, gear 78 is utilized as apinion to drive rack 70. Thus, when pinion gear 78 is being driven in acounterclockwise direction, rack 70 is being moved upward as viewed inFIG. 4.

Similarly, a band 308 secured at one end to relay 10B is passed aroundwheel 32B in the clockwise direction as viewed from the bottom (i.e. inthe opposite direction from the direction in which band 30A is passedaround wheel 32A) and terminated in a connection to one end of spring368. Spring 36B is connected at its other end to pin 38B mounted onhousing 14. Wheel 32B is connected to the housing of overrunning clutch428 which clutch is passed through by shaft 80. Counterclockwisemovement of shaft 80 is prevented by overrunning clutch 46B which issecured to gimble 48B mounted on housing 14. Shaft 80 also terminates atits other end in differential gear box 76.

In operation, it will be assumed that the device shown in FIG. 3 is anincremental positioner wherein a signal on line 82 indicates a desiredupward movement of rack 70 while a signal on line 84 indicates a desireddownward movement of the rack. Thus, a signal on line 82 may, forexample, be a pulse of duration equal to the number of cycles of source20 which are required to effect a desired increment of movement of rack70 in the upward direction. In the alternative, the signal on line 82may represent the count of the number of AC cycles required for such anincrement of movement with this count being stored in control circuit 72and being decremented once for each cycle of source 20. When the countequals zero the switch passing the AC signal to relay 10A is opened.Since the particular control circuit utilized does not form part of thepresent invention, the above indicated controls are mentioned merely forpurposes of illustration and any suitable method of control may beutilized.

When relay 10A is energized, band 30A is cyclically pulled in theclockwise direction by relay 10A and then restored by being pulled in acounterclockwise direction by the action of spring 36A. Clutches 42A and46A function, as described previously for the embodiment of theinvention shown in FIG. 1, to permit only a small counterclockwiseincrement of motion to shaft 74 for each cycle of relay 10A. Thisincrement is applied through differential gear box 76 to pinion 78causing rack 70 to be moved upward by a similar small amount.

Rack 70 is moved downward as a result of clockwise motion of pinion 78caused by shaft 80 as a result of the energization of relay 10B. Exceptfor direction, the manner in which this rotation is caused is identicalto that described above and further description is not believednecessary.

While in the preferred embodiments of the invention described above thevibrational movement has been obtained from a relay, it is apparent thateven finer increments of motion could be obtained by utilizing someother vibrating element as, for example, a piezoelectric crystal. Thecontrol circuits mentioned above, as previously indicated, are merelyillustrative with the particular control circuitry employed depending onthe specific application of the device.

Thus, while the invention has been particularly shown and described withreference to preferred embodiments thereof, it will be understood bythose skilled in the art that the foregoing and other changes in formand details may be made therein, without departing from the spirit andscope of the invention.

What is claimed is:

l. A device for moving a first rotatable member from a first position toa second position in a plurality of small incremental steps comprising:

an electrically energized vibrator;

a second rotatable member;

a band secured at one end to said vibrator and engaging said secondrotatable member in a manner such as to impart a rotary vibrationalmovement thereto in response to the vibration of said vibrator, saidmovement being, for each vibration cycle, a small fraction of arevolution of said member;

means for securing said first and second rotating members together whensaid second member moves in one direction during a vibration cycle whiledecoupling said members when said second member moves in the oppositedirection during a vibration cycle;

whereby said first rotatable member is incrementally advanced in saidone direction for each vibration cycle of said second rotatable member;

a third rotatable member adapted to rotate in either said one directionor said opposite direction; and

means for coupling said first and third rotating members in a mannersuch that said members rotate together when said third member is beingdriven in said one direction but are free to rotate relative to eachother when said third member is driven in said other direction.

2. A device of the type described in claim 1 including means for drivingsaid third member in said other direction, said means including anelectrically energized vibrator.

3. A device for moving a first rotatable member from a first position toa second position in a plurality of small incremental steps comprising:

an electrically energized vibrating relay;

a second rotatable member;

a band secured at one end to said vibrating relay and at the other endto a resilient means, said band engaging said second rotatable member ina manner such as to impart a rotary vibrational movement thereto inresponse to the vibration of said relay, said movement being, for eachvibration cycle, a small fraction of a revolution of said member, saidresilient means being adapted to restore the second rotatable member toits initial position during each vibration cycle; and

means for securing said first and second rotating members together whensaid second member moves in one direction during a vibration cycle whiledecoupling said members when said second member moves in the oppositedirection during a vibration cycle;

4. A device of the type described in claim 3 wherein said one directionis the direction in which said rotatable members are rotated by saidresilient means and said opposite direction is the direction said secondrotatable member is driven by said relay.

1. A device for moving a first rotatable member from a first position toa second position in a plurality of small incremental steps comprising:an electrically energized vibrator; a second rotatable member; a bandsecured at one end to said vibrator and engaging said second rotatablemember in a manner such as to impart a rotary vibrational movementthereto in response to the vibration of said vibrator, said movementbeing, for each vibration cycle, a small fraction of a revolution ofsaid member; means for securing said first and second rotating memberstogether when said second member moves in one direction during avibration cycle while decoupling said members when said second membermoves in the opposite direction during a vibration cycle; whereby saidfirst rotatable member is incrementally advanced in said one directionfor each vibration cycle of said second rotatable member; a thirdrotatable member adapted to rotate in either said one direction or saidopposite direction; and means for coupling said first and third rotatingmembers in a manner such that said members rotate together when saidthird member is being driven in said one direction but are free torotate relative to each other when said third member is driven in saidother direction.
 2. A device of the type described in claim 1 includingmeans for driving said third member in said other direction, said meansincluding an electrically energized vibrator.
 3. A device for moving afirst rotatable member from a first position to a second position in aplurality of small incremental steps comprising: an electricallyenergized vibrating relay; a second rotatable member; a band secured atone end to said vibrating relay and at the other end to a resilientmeans, said band engaging said second rotatable member in a Manner suchas to impart a rotary vibrational movement thereto in response to thevibration of said relay, said movement being, for each vibration cycle,a small fraction of a revolution of said member, said resilient meansbeing adapted to restore the second rotatable member to its initialposition during each vibration cycle; and means for securing said firstand second rotating members together when said second member moves inone direction during a vibration cycle while decoupling said memberswhen said second member moves in the opposite direction during avibration cycle;
 4. A device of the type described in claim 3 whereinsaid one direction is the direction in which said rotatable members arerotated by said resilient means and said opposite direction is thedirection said second rotatable member is driven by said relay.